package net.javawind.t_api.filters;

import java.io.IOException;

import javax.servlet.Filter;
import javax.servlet.FilterChain;
import javax.servlet.FilterConfig;
import javax.servlet.ServletException;
import javax.servlet.ServletRequest;
import javax.servlet.ServletResponse;

/**
 * JSP/Servlet 编码过滤器
 * 
 * @author <a href="http://blog.javawind.net">Xuefang Xu</a>
 * @Data 2010-01-21
 * @Version 1.0.0
 */

public class SetCharacterEncodingFilter implements Filter {
    protected String encoding = null;
    protected FilterConfig filterConfig = null;
    protected boolean ignore = true;
    
    public void destroy() {
        this.encoding = null;
        this.filterConfig = null;
    }

    public void doFilter(ServletRequest request, ServletResponse response,
    			FilterChain chain)throws IOException, ServletException{
    	if (ignore || (request.getCharacterEncoding() == null)) {
    		String encoding = selectEncoding(request);
    		if (encoding != null)
    			request.setCharacterEncoding(encoding);
    	}
    	chain.doFilter(request, response);
    }

    public void init(FilterConfig filterConfig) throws ServletException {
    	this.filterConfig = filterConfig;
        this.encoding = filterConfig.getInitParameter("encoding");
        String value = filterConfig.getInitParameter("ignore");
        if (value == null)
            this.ignore = true;
        else if (value.equalsIgnoreCase("true"))
            this.ignore = true;
        else if (value.equalsIgnoreCase("yes"))
            this.ignore = true;
        else
            this.ignore = false;
    }

    protected String selectEncoding(ServletRequest request) {
        return (this.encoding);
    }
}
